IL-31, a newly identified cytokine, has been found to result in dermatitis-like symptoms when over-expressed in mice. See, Dillon, et al., Nature Immunol. 5:752-760, 2004. These symptoms can be alleviated by use of antagonists that block, inhibit, reduce, antagonize or neutralize the activity of IL-31, and include anti-IL-31 antibodies. Also see, U.S. patent application Ser. No. 10/352,554, filed Jan. 21, 2003 (U.S. Patent Publication No. 2003-0224487), now U.S. Pat. Nos. 7,064,186, 7,425,325, and 7,459,293.
Monoclonal antibody technology has provided a vast array of therapeutics as well as diagnostics for use in identifying and treating disease. A number of recombinant or biosynthetic molecules comprising rodent antigen-binding sites have been described. Particularly, molecules having rodent antigen-binding sites built directly onto human antibodies by grafting only the rodent binding site, rather than the entire variable domain, into human immunoglobulin heavy and light chain domains have been described. See, e.g., Riechmann et al. (1988) Nature 332:323-327 and Verhoeyen et al. (1988) Science 239:1534-1536. Molecules having an antigen-binding site wherein at least one of the complementarity determining regions (CDRS) of the variable domain is derived from a murine monoclonal antibody and the remaining immunoglobulin-derived parts of the molecule are derived from human immunoglobulin have been described in U.K Patent Publication No. GB 2,276,169, published Sep. 21, 1994. A number of single chain antigen-binding site polypeptides and single chain Fv (sFv) molecules have also been described. See, e.g., U.S. Pat. Nos. 5,132,405 and 5,091,513 to Huston et al.; and U.S. Pat. No. 4,946,778 to Ladner et al.
Mouse anti-human IL-31 monoclonal antibodies have been described previously in U.S. patent application Ser. No. 11/430,066, filed May 8, 2006 (U.S. Patent Publication No. 2006-02752960) that describes mouse monoclonal antibodies that recognize human IL-31 and can be used to generate chimeric antibodies. However, chimeric antibodies may cause immunogenicity and humanized mouse—anti-human IL-31 antibodies are desirable. Humanized antibodies generally have at least three potential advantages over mouse or in some cases chimeric antibodies for use in human therapy: (1) Because the effector portion is human, it may interact better with the other parts of the human immune system (e.g., destroy the target cells more efficiently by complement-dependent cytotoxicity (CDC) or antibody-dependent cellular cytotoxicity (ADCC)); (2) The human immune system should not recognize the framework or constant region of the humanized antibody as foreign, and therefore the antibody response against such an injected antibody should be less than against a totally foreign mouse antibody or a partially foreign chimeric antibody; and (3) Injected mouse antibodies have been reported to have a half-life in the human circulation much shorter than the half-life of normal antibodies (D. Shaw et al., J. Immunol., 138, 4534-4538 (1987)). Injected humanized antibodies will presumably have a half-life more similar to naturally occurring human antibodies, allowing smaller and less frequent doses to be given.
Thus, there is a need for molecules which provide humanized variable region amino acid sequences for the mouse anti-human IL-31 antibodies for treating IL-31 mediated inflammation.